Dragon priest with mind control tech and archbishop is a very fun, ~tier 2ish, thief priest deck.

Archbishop is extremely good again Cube Warlock (tier 1) and Control Warlock (tier 2), almost guarantees win if it goes to fatigue, it's also good again priest match ups and mage, to get face damage or ice blocks. It can work against rogue, if the weapon gets shuffled.

Also mind control tech in a dragon priest deck gives a better chance against the tier 1 aggro decks, especially if you get a duskbreaker in the early game. Playing Grand archivist before Archbishop is advisable for winning, but a lot less fun.

No, it's quite a tech-card, and a very good one. Mill decks are now the plague in wild, put him in your deck, if you don't overdraw him and you play him in any kind of priest, you automatically win. Mill rogue wins with card advantage, without card advantage you win.

Became a must-have in every priest deck with the new Warlock Legendary in Kobolds & Catacombs. What's that? You destroy my deck? What about i take yours? I already use this in my Priest deck. I win every battle vs. a mill rogue or dead mans hand warrior. :-)